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Biomedical subjects

W G Wood

Publications and source records attributed to W G Wood.

At least 19 recordsLinked to original sources
PubMed1992

Regulation of human embryonic globin genes zeta 2 and epsilon in stably transformed mouse erythroleukemia cells.

Previous work has suggested that the promoter regions of the human embryonic zeta 2 and epsilon globin genes contain negative regulatory regions that could play a role in the repression of these genes in postembryonic erythroblasts. We have examined this possibility by studying the expression of these genes in mouse erythroleukemia cells, an adult erythroid cell line that might be expected to contain repressor molecules that would bind to the putative negative regulatory regions. When attached to appropriate upstream regulatory elements (alpha HS-40 and beta HS1,2) both the zeta and epsilon genes were expressed in these cells at a low level, but no increase in expression was observed when similar constructs lacking the proposed negative regulatory sequences were introduced into these cells. These results cast doubt on the possibility that these sequences play a major role in the developmental repression of the embryonic globin genes, unless they function only in a normal chromosomal organization.

Adenine Phosphoribosyltransferase↗
PubMed1992

[C-reactive protein in the urine. The differential diagnosis of renal functional disorders following kidney transplantation].

A prospective study was undertaken in 73 patients (24 women, 49 men; mean age 47.9 [21-64] years) after renal transplantation to discover whether the presence of C-reactive protein in urine (CRPu) and its serum concentration (CRPs) are of value in the differential diagnosis of abnormal function in the transplanted kidney. CRPu concentration was measured with a highly sensitive immunoluminometric assay (minimal threshold value 6 micrograms/l). CRPu was demonstrated in 36 histologically proven rejection episodes and 21 bacterial infections proven by culture. In contrast, no CRPu was demonstrated when the course was normal and in individual cases of cyclosporin renal toxicity, as well as in 27 of 34 cases of cytomegalovirus infection. In addition, the CRPs to CRPu ratio was a sensitive means of distinguishing between rejection (CRPs/CRPu less than 1) and bacterial infection (CRPs/CRPu greater than 1). Determining CRPu concentration thus proved to be useful in the initial monitoring of renal transplantation before starting any specific urinary protein diagnosis, as well as (together with CRPs) in the diagnosis of severe posttransplantation complications.

Adult↗
PubMed1992

Analysis of the human alpha globin upstream regulatory element (HS-40) in transgenic mice.

We have analysed the effect of a 1.4 kb segment of DNA containing the upstream alpha globin regulatory element (HS-40) on human alpha globin gene expression in fetal mice and lines of transgenic mice. High levels of tissue-specific, human alpha mRNA expression were seen in all transgenic animals and in this sense expression was position independent. However, the level of human alpha mRNA expression per integrated gene copy decreased during development and was inversely related to copy number. The limitation in expression with increasing gene copy number was shown to be in cis since homozygotes for the transgene produced twice as much human alpha mRNA as hemizygotes. In many respects HS -40 appears similar to single elements within the previously described beta globin locus control region and in cross breeding experiments we have shown that HS -40 behaves in a similar manner to such elements in transgenic mice.

Animals↗
PubMed1992

Elastase alpha 1-proteinase inhibitor and lactoferrin concentrations in endotracheal aspirates of ventilated newborns.

Bacterial colonization of the tracheo-bronchial tree is common and an established risk factor for infection in ventilated newborns. Elastase, a highly active proteinase, and lactoferrin, an iron-binding protein and potential modulator of the inflammatory process, are both major constituents of either azurophilic or primary granules of neutrophilic granulocytes, released by activation of these cells during the inflammatory response. Since both elastase, complexed with its major inhibitor alpha 1-proteinase inhibitor (E alpha 1-Pl), and lactoferrin (Lf) are indicators of granulocyte activation during bacterial infection, they may indicate infectious inflammation at the tracheobronchial site. To study whether these substances in a single suction probe may serve this purpose, we obtained 82 tracheo-bronchial aspirates routinely from 16 ventilated newborns with a median gestational age of 31.5 (range, 25-39) weeks for laboratory analysis and bacterial cultures. Systemic inflammatory response by differential white blood cell count and C-reactive protein (CRP) was monitored simultaneously. The median E alpha 1-Pl level was significantly elevated in culture-positive aspirates (1,005 micrograms/L; range, less than 30-29,240 micrograms/L) in contrast to culture-negative samples (158 micrograms/L; range, less than 30-1,408 micrograms/L). In addition to a diagnostic sensitivity of 77%, E alpha 1-Pl offered a high specificity of 88%, a positive predictive value of 97%, and a negative predictive value of 73%. In contrast, median Lf concentration (10.6; range, 0.3-58.3 mg/L vs. 11.7; range, 1.6-158 mg/L) showed no correlation with culture results. Of the culture-positive aspirates 36% corresponded with systemic signs of an acute inflammatory response, such as elevated I/T-ratio and CRP.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1992

Na pump and plasma membrane structure in L-cell fibroblasts expressing rat liver fatty acid binding protein.

Although the intracellular fatty acid binding proteins have been investigated for nearly two decades and purified proteins are now available, little is known regarding the function of these proteins in intact cells. Therefore, L-cell fibroblasts transfected with cDNA encoding for rat liver fatty acid binding protein (L-FABP) were examined as to whether L-FABP expression in intact cells modifies plasma membrane enzyme activities, fluidity, and lipids. Plasma membrane Na/K-ATPase activity was 65.9 +/- 18.7 and 38.6 +/- 22.8 (P less than 0.001) nmol/mg protein x min for control and high-expression transfected cells, respectively. Consistent with this observation, [3H] ouabain binding to whole cells was significantly decreased from 3.7 +/- 0.3 to 2.0 +/- 0.8 pmol ouabain bound/mg cell protein in control and high-expression cells, respectively, whereas the cell's affinity for ouabain was not significantly altered. Unexpectedly, Western blot analysis indicated that transfected cells had higher levels of Na+, K(+)-ATPase protein; in contrast, the activities of 5'-nucleotidase and Mg-ATPase were unaltered. The effects of L-FABP expression on plasma membrane Na/K-ATPase function appeared to be mediated through alterations in plasma membrane lipids and/or structure. The plasma membrane cholesterol/phospholipid ratio decreased and the bulk plasma membrane fluidity increased in the high-expression cells. In conclusion, plasma membrane Na/K-ATPase activity in L cells may be regulated in part through expression of cytosolic L-FABP.

Animals↗
PubMed1992

A single beta-globin locus control region element (5' hypersensitive site 2) is sufficient for developmental regulation of human globin genes in transgenic mice.

The beta-globin gene complex is regulated by an upstream locus control region (LCR) which is responsible for high-level, position-independent, erythroid-cell-specific expression of the genes in the cluster. Its role in the developmental regulation of beta-like globin gene transcription remains to be established. We have examined the effect of a single LCR element, hypersensitive site 2 (HS2), on the developmental regulation of the human fetal gamma and adult beta genes in transgenic mice. In mice bearing HS2A gamma beta and HS2G gamma A gamma-117 delta beta human globin gene constructs, switching from gamma- to beta-gene expression begins at about day 13.5 of gestation and is largely completed shortly after birth. The larger construct also demonstrates a switch in G gamma- to A gamma-gene expression during the gamma-to-beta switch similar to that observed during normal human development. We conclude that HS2 alone is sufficient for developmental regulation of the human beta-globin genes.

Aging↗
PubMed1992

Towards an understanding of the mode of action of Bacillus Calmette-Guérin-therapy in bladder cancer treatment, especially with regard to the role of fibronectin.

The interaction between Bacillus Calmette-Guérin (BCG) and the host was investigated after repeated intravesicular BCG-therapy for superficial bladder cancer. Studies were performed on (a) the local reaction in the bladder, (b) the systemic reaction, and (c) short and long term interactions in both the bladder and the serum/plasma. The analytes measured included anti-BCG IgA and IgG, fibronectin, lactoferrin, elastase-alpha 1-proteinase inhibitor, myeloperoxidase and alpha 2-proteinase inhibitor. All analytes, with the exception of alpha 2-proteinase inhibitor, were measured in both serum/plasma and urine. An additional group of 94 patients undergoing bronchoalveolar lavage was used for comparison with other diseases affecting mucous membranes. In vitro studies on human bladder in culture were also carried out to study the relationship between BCG, elastase and fibronectin. The results revealed a normal defence reaction, in which IgA and IgG antibodies specific to BCG were produced by the host. Maximal concentrations of all analytes in urine were found about 4 h after BCG instillation. Immunoglobulins, soluble fibronectin, and granulocyte markers all appeared in urine after instillation and all showed a similar time course. The in vitro study showed the synergistic effect of elastase and BCG in stimulating the host defence reaction. The relationship between BCG and fibronectin can be seen as fortuitous but not indicative of the efficacy of BCG-therapy in patients with superficial bladder cancer.

Administration, Intravesical↗
PubMed1992

[Myeloperoxidase, lactoferrin and elastase in bronchoalveolar lavage and plasma in pneumonia].

Neutrophilic granulocytes in the lower respiratory tract are of decisive importance for the elimination of pathogenic germs in bacterial pneumonia. On the other hand, the liberation of phagocyte products (e.g. elastase) can result in tissue damage in the parenchyma of the lungs. For this reason, we determined in patients suffering from acute pneumonia (n = 21), in patients with acute pneumonia associated with immunosuppression (n = 12), in patients who had overcome their pneumonia (n = 9) and in controls (n = 17) in bronchoalveolar lavage (BALF) and in plasma, the concentration of the locally produced granulocyte products myeloperoxidase (MPO), lactoferrin (LF) and elastase-alpha 1 proteinase complex (ELA) as well as of the alpha 1 proteinase inhibitor (alpha 1 Pi) and alpha 2 proteinase inhibitor (alpha 2 Pi) via chemoluminescence immunoassay, and compared the same with the differential cell count in the BALF. The protein concentrations were referred to the albumin concentration (Alb) for standardisation. This concentration did not differ significantly between the various patients and control groups. The BALF concentration of ELA in the group with pneumonia (median: 86.3 micrograms/l or 8.5 micrograms/mg Alb) was about eight times higher than in the group of patients suffering from pneumonia with immunosuppression (median: 16 micrograms/l or 1.0 micrograms/l Alb, p less than 0.001) or in whom the pneumonia was no longer present (17.6 micrograms/l or 0.5 micrograms/mg), and approximately 40 times higher than in the control group (3 micrograms/l or 0.2 micrograms/mg, respectively). Similar results were obtained for LF (61 micrograms/mg Alb vs. 11.3; 16.8 and 5.9 micrograms/mg; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Regulation of human fetal and adult globin genes in mouse erythroleukemia cells.

We have examined whether transfected mouse erythroleukaemia (MEL) cells can be used to examine differential expression of human gamma- and beta-globin genes. These cells, which express only their adult globin genes, will transcribe the human adult beta gene but not the fetal gamma genes when they are introduced on an intact human chromosome 11 by cell fusion. However, MEL cells stably transfected with the human A gamma gene attached to one of the active elements (HS2) of the beta-globin locus control region (LCR) readily produce gamma-globin mRNA in amounts equivalent to those seen with a comparable beta gene insert. When both beta and gamma genes are attached to HS2, equal amounts of beta A gamma mRNAs are produced, irrespective of the gene order. Furthermore, when HS2 is inserted into the 5' end of a 40-kb cosmid containing the G gamma A gamma-117 delta beta genes in their normal chromosomal organization (but with the Greek HPFH -117 A gamma gene mutation), it directs expression of readily detectable amounts of G gamma A gamma and beta-globin mRNAs in MEL cells. Therefore, under these circumstances we have observed no competition between beta and gamma genes for expression in MEL cells. These findings suggest that MEL cells are capable of perpetuating regulatory information involved in developmental control when it is provided by an intact chromosome, but are incapable of reconstructing such information on transfected DNA.

Adenine Phosphoribosyltransferase↗
PubMed1991

Transmembrane distribution of sterol in the human erythrocyte.

The transbilayer cholesterol distribution of human erythrocytes was examined by two independent techniques, quenching of dehydroergosterol fluorescence and fluorescence photobleaching of NBD-cholesterol. Dehydroergosterol in conjunction with leaflet selective quenching showed that, at equilibrium, 75% of the sterol was localized to the inner leaflet of resealed erythrocyte ghosts. NBD-cholesterol and fluorescence photobleaching displayed two diffusion values in both resealed ghosts and intact erythrocytes. The fractional contribution of the fast and slow diffusion constants of NBD-labelled cholesterol represent its inner and outer leaflet distribution. At room temperature the plasma membrane inner leaflet of erythrocyte ghosts as well as intact erythrocytes cells contained 78% of the plasma membrane sterol. The erythrocyte membrane transbilayer distribution of sterol was independent of temperature. In conclusion, dehydroergosterol and NBD-cholesterol data are consistent with an enrichment of cholesterol in the inner leaflet of the human erythrocyte.

Cholesterol↗
PubMed1991

[Beta 2-microglobulinuria in cytomegalovirus infections following kidney transplantation].

In a prospective study the occurrence of cytomegalovirus (CMV) infection was diagnosed by demonstrating CMV-immediate early antigen (IEA) in the blood in 13 out of 68 (19%) patients who had undergone renal transplantation (27 women, 41 men, mean age 46.3 [21-64] years). Twenty-four hour urine samples were collected at the same time for quantitative determination of selected marker proteins by immunoluminometric assays (IgG and transferrin as glomerular markers, alpha 1-microglobulin and beta 2-microglobulin as tubular markers). In all 13 confirmed cases of CMV infection there was an isolated rise in urinary beta 2-microglobulin excretion amounting to more than three times the normal. In 11 of the 13 cases the beta 2-microglobulinuria was noted before the CMV-IEA test became positive. This suggests that quantitative assay of beta 2-microglobulin in the urine may be of value in the early diagnosis of CMV infection--a matter of some prognostic importance--and may hence offer additional support for therapeutic decisions.

Adult↗
PubMed1991

Characterization of the major regulatory element upstream of the human alpha-globin gene cluster.

The major positive regulatory activity of the human alpha-globin gene complex has been localized to an element associated with a strong erythroid-specific DNase I hypersensitive site (HS -40) located 40 kb upstream of the zeta 2-globin mRNA cap site. Footprint and gel shift analyses of the element have demonstrated the presence of four binding sites for the nuclear factor GATA-1 and two sites corresponding to the AP-1 consensus binding sequence. This region resembles one of the major elements of the beta-globin locus control region in its constitution and characteristics; this together with evidence from expression studies suggests that HS -40 is a primary element controlling alpha-globin gene expression.

Base Sequence↗
PubMed1991

The establishment and evaluation of luminescent-labelled immunometric assays for prostate-specific antigen-alpha 1-antichymotrypsin complexes in serum.

Prostate-specific antigen is found in the prostate in two forms, one with a low (30,000) and one with a high (100,000) relative molecular mass. The latter has recently been found to be a complex of prostate-specific antigen with alpha 1-antichymotrypsin. Immunoluminometric assays were designed for the prostate-specific antigen-alpha 1-antichymotrypsin complex as well as for alpha 1-antichymotrypsin, the former being compared with a commercially available radioimmunoassay for prostate-specific antigen (ProsChek RIA-Yang Laboratories). The precision of the immunoluminometric assays was acceptable (intra-assay variation less than 7%; inter-assay variation less than 8.5%) in the measuring ranges 0-90 micrograms/l for the prostate-specific antigen-alpha 1-antichymotrypsin complex and 0-12 g/l for alpha 1-antichymotrypsin. The correlation between the assays for prostate-specific antigen and prostate-specific antigen-alpha 1-antichymotrypsin complex was acceptable, showing a correlation coefficient r = 0.83 after double logarithmic transformation, or r = 0.85 using the Spearman rank correlation on 131 data pairs. Extremely high alpha 1-antichymotrypsin levels (above 2 g/l) caused interference in the prostate-specific antigen-alpha 1-antichymotrypsin complex assay. Such levels, although rare, are encountered in pulmonary inflammatory disease. The reference ranges for the three assays were found to be as follows: prostate-specific antigen 0.13-4.63 micrograms/l, prostate-specific antigen-alpha 1-antichymotrypsin complex 0.08-1.78 microgram/l, and for alpha 1-antichymotrypsin 0.27-0.61 g/l. These values were obtained from 82 hospitalised males for the first two assays and from 80 males and females free from infection for the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1991

Helicobacter pylori: histological and serological study on gastric and duodenal ulcer patients in Estonia.

We have examined the occurrence of Helicobacter pylori (HP) infection in 86 Estonian gastric ulcer (GU) and 25 duodenal ulcer (DU) patients. Diagnosis of the HP infection was made histologically (modified Giemsa) from gastric biopsy specimens, and serologically by parallel use of two enzyme-linked immunosorbent assays for IgG antibodies to HP in patient sera. The infection was diagnosed simultaneously by all three methods in 84% of the GU and 84% of the DU patients. The infection was revealed histologically in 88% of the GU and 92% of the DU patients, and serologically by either of the two methods in 94% and 92% of the GU and DU patients, respectively. HP infection was absent by all three methods in one GU patient only, this patient being the only subject who showed normal gastric mucosa in conventional histology. These observations show that HP infection is very common in patients with peptic ulcer in Estonia. In addition, the findings suggest that the serological assays will find a small proportion (15%) of ulcer patients with antibodies against HP but no histologically detectable bacteria.

Adult↗
PubMed1991

Membrane cholesterol dynamics: cholesterol domains and kinetic pools.

Nonreceptor mediated cholesterol uptake and reverse cholesterol transport in cells occur through cellular membranes. Thus, elucidation of cholesterol dynamics in membranes is essential to understanding cellular cholesterol accumulation and loss. To this end, it has become increasingly evident that cholesterol is not randomly distributed in either model or biologic membranes. Instead, membrane cholesterol appears to be organized into structural and kinetic domains or pools. Cholesterol-rich and poor domains can even be observed histochemically and physically isolated from epithelial cell surface membranes. The physiologic importance of these domains is 2-fold: (i) Select membrane proteins (receptors, transporters, etc.) are localized in either cholesterol-rich or cholesterol-poor domains. Consequently, the structure and properties of the domains rather than of the bulk lipid may selectively affect the function of proteins residing therein. (ii) Kinetic evidence suggests that cholesterol transport through and between membranes may occur through specific domains or pools. Regulation of the size and properties of such domains may be controlling factors of cholesterol transport or accumulation in cells. Recent technologic advances in the use of fluorescent sterols have allowed examination of cholesterol domain structure in model and biologic membranes. These techniques have been applied to examine the role of high-density lipoprotein, cholesterol lowering drugs, and intracellular lipid transfer proteins in membrane sterol domain structure and sterol movement between membranes.

Animals↗
PubMed1991

Evaluation of a sensitive immunoenzymometric assay for thyrotropin suitable for emergency and paediatric use.

This short communication compares a luminescent-labelled immunometric assay (BeriLux) with an enzyme-labelled immunometric assay (NovaPath) for thyrotropin determinations. The NovaPath assay lends itself to paediatric use, because it only uses 25 microliters sample, and to emergency use, because the main incubation can be reduced to 30 minutes. The correlation between both kits was acceptable (r = 0.825, n = 167 data pairs) although the NovaPath kit gave lower values than the BeriLux it (Median-BeriLux 1.00 mU/l, NovaPath 0.70 mU/l, p less than 0.001 = Wilcoxon Test). From 167 sera (range less than 0.01-44 mU/l) 3 gave discrepant values, being euthyroid in the BeriLux kit and hyperthyroid in the NovaPath kit. All 3 patients were undergoing thiamazole (Favistan) therapy at the time of sampling. The coefficients of variation were lower in the BeriLux kit (intraassay less than 4.5%, interassay less than 5.5% for the range 0.1-50 mU/l) than in the NovaPath kit (intraassay less than 7.5%, interassay less than 12.5%). This reflects the larger dynamic range (signal/noise ratio) of the BeriLux kit.

Child↗